Wifi Fears Are "Unfounded"

Scientists have said that fears raised by the BBC programme Panorama about the safety of wifi are unfounded. Panorama reported on Monday (May 21) night that radiation levels from wi-fi in one school were up to three times the level of mobile phone mast radiation.

Sir William Stewart, chairman of the Health Protection Agency, said that there needed to be an urgent review of wifi safety after he provided the programme with evidence that that low-level radiation - from devices like mobile phones and wi-fi - did cause damage to people's health.

However, some experts in the scientific community have disagreed with Sir William. Professor Lawrie Challis, of Nottingham University, said: "Wi-fi seems unlikely to pose any risk to health." Prof Challis, chairman of the Mobile Telecommunications and Health Research (MTHR) programme management committee, said: "Wi-fi exposures are usually very small - the transmitters are low power and some distance from the body. They can be near to the body, however, when a laptop is on one's lap and my own view is that just as we encourage young children not to use mobile phones we should also encourage them to use their laptops on a table rather than their lap, if they are going online for a long time."

During its investigation, reporters from Panorama visited a a school in Norfolk, with more than 1,000 pupils, to compare the level of radiation from a typical mobile phone mast with that of wi-fi in the classroom. Readings showed the height of wi-fi signal strength to be three times higher in the school classroom than the main beam of radiation intensity from a mobile phone mast.

Medical physics expert Professor Malcolm Sperrin told BBC News that the fact wi-fi radiation in a particular school was three times higher than a mobile phone mast was irrelevant, as there is currently no evidence of a link to any health effects. He said: "Wi-fi is a technique using very low intensity radio waves. Whilst similar in wavelength to domestic microwave radiation, the intensity of wi-fi radiation is 100,000 times less than that of a domestic microwave oven.

Furthermore, tissue can only be effectively heated by a wavelength that is closely matched to the absorption, and there are strict guidelines for ensuring such absorption peaks are avoided."

The Health Protection Agency had previously said that sitting in a wi-fi hotspot for a year resulted in receiving the same dose of radio waves as making a 20-minute mobile phone call.

Prof Sperrin added: "Radio waves (wi-fi) and other non-ionising radiations have been part of our lives for a century or more and if such effects were occurring then damage or other untoward effects would have been recorded and studied. Research is still proceeding in this area at leading centres in many countries but evidence points to wi-fi transmissions being well below any likely threshold for human effects."

Despite concerns about wifi and its effects on people's health being raised by the likes of Professor Olle Johansson, of the Karolinska Institute in Sweden, and Professor Henry Lai, from Washington state university, Prof Sperrin was joined by Professor Will J Stewart, fellow of the Royal Academy of Engineering, in his defence of such technology.

Prof Stewart said: "Science has studied the safety of mobile phones for many years and the overwhelming body of evidence shows little cause for concern. As for wi-fi, although these devices operate at a modestly different frequency to mobiles they also operate at a lower power level over a much shorter-range. "Add to the fact that high-bandwidth wi-fi devices are less likely to be head-mounted and there really is no issue here. This is not to say that all electromagnetic radiation is necessarily harmless - sunlight, for example, poses a significant cancer risk; so if you are using your laptop on the beach make sure and get some shade."

Prof Sperrin concluded his defence of wifi by saying that it was impossible to prove a negative and that there was no justification in discarding wi-fi until it could be proved unsafe. "The educational benefits from using laptops and having access to information far outweigh any unproven fears over the safety of wi-fi. I am more concerned about the heat laptops generate and the impact that could on sensitive parts of the body."